A freelance motor racing journalist and television presenter, Costello has won many other racing awards and received the Member of the Most Excellent Order of the British Empire (MBE) in 2009.
She had previously raced at Hampton Downs at the Mike Pero Barry Sheene Motorcycle Classic in October, but said she had to come back when Tauranga sidecar competitor Tracey Bryan and her husband Steve insisted she join them.
"I need to be careful what I wish for right now, because it feels like all my dreams are coming true and this one is thanks to Tracey and Steve Bryan," she said.
"Tracey is going to the TT next year and I was speaking to her husband Steve about that when we got on to chatting about Wanganui.
"I can't wait to get back and enjoy even more Kiwi hospitality, including a real Kiwi Christmas [with sun] and to take in the atmosphere at the famous Cemetery Circuit."
Greg Boyd, of Boyd Motorcycles in Hamilton, has supplied her with a KTM DUKE 690R to race the F3 and Bears class, and Costello said she is also hoping to compete in the Classic events.
"I'm still waiting to hear about that but I had so much fun on the beautiful Bruce Verdon McIntosh Manx Norton that it would be great to race it again."
Costello came fifth in the Classic TT this year.
"I started racing on short circuits, a long time ago. I'm now more of a real road racer.
"So I'm really looking forward to racing at Wanganui and hanging out with my everyone.
"I've fallen in love with New Zealand."
The three-round Suzuki Series starts at Hampton Downs on December 7, continues at Manfeild the following week, then reaches its finale on Boxing Day in Wanganui.